..That the mechanisms by which glycoprotein substrates are recruited for degradation diverge at the level of signal recognition reflects a previously unappreciated component of cellular differentiation in higher eukaryotes...

LeMAN4 endo-beta-mannanase from ripe tomato fruit can act as a mannan transglycosylase or hydrolase

Roswitha SchröderMt Albert Research Centre, The Horticulture and Food Research Institute of New Zealand, Private Bag 92 169, Auckland, New ZealandPlanta 224:1091-102. 2006

..sequence tag clones were identified by sequence similarity to mammalian and yeast oligosaccharide-processing mannosidases, and the full-length coding region of the putative mannosidase homolog was isolated by a combination of 5'-..

Glycoprotein biosynthesis in Saccharomyces cerevisiae. Isolation and characterization of the gene encoding a specific processing alpha-mannosidase

..Therefore, the Yloch1 mutant strain can be used as a host to produce glycoproteins lacking the outer-chain mannoses and further developed for the production of therapeutic glycoproteins containing human-compatible oligosaccharides...

..pastoris alg3 deletion mutant in the presence and absence of the outer chain initiating Och1p alpha-1,6-mannosyltransferase activity suggests that the PpOch1p has a broader substrate specificity compared to its S. cerevisiae counterpart...

Single nucleotide polymorphism-mediated translational suppression of endoplasmic reticulum mannosidase I modifies the onset of end-stage liver disease in alpha1-antitrypsin deficiency

..Moreover, the human-type high-mannose oligosaccharide Man(5)GlcNAc(2) was the major N-glycan of the glyco-engineered trans-sialidase, indicating that N-glycan engineering can be effectively accomplished in P. pastoris...

Elucidation of the molecular logic by which misfolded alpha 1-antitrypsin is preferentially selected for degradation

..These results suggest a role for the Man8GlcNAc2 oligosaccharide in the degradation process. They may indicate the presence of a Man8GlcNAc2-binding lectin involved in targeting of misfolded glycoproteins to degradation in S. cerevisiae...

..The structures also provide insight into the specificity of this class of enzymes and provide a blueprint for the future design of novel inhibitors that prevent degradation of misfolded proteins in genetic diseases...

..acid sequence of AtEBM has distinct differences from those of the bacterial, fungal, and animal exo-type beta-mannosidases. Indeed, AtEBM-like genes are only found in plants, indicating that endo-beta-mannosidase is a plant-specific ..

The transmembrane domain of murine alpha-mannosidase IB is a major determinant of Golgi localization

..A GFP chimera lacking the entire cytoplasmic tail was found in both the ER and the Golgi. These results indicate that the transmembrane domain of alpha1,2-mannosidase IB is a major determinant of Golgi localization...

Isolation, characterization, and expression of cDNAs encoding murine alpha-mannosidase II, a Golgi enzyme that controls conversion of high mannose to complex N-glycans

..Expression of the genes, as determined by the presence of mRNA transcripts in Northern hybridization analyses, occurs in the endosperm of germinated seeds; no transcripts are detected in hypocotyls, cotyledons, roots or leaves...

Molecular cloning and primary structure of Man9-mannosidase from human kidney

..DCW1 and DFG5 mRNA levels peaked in the G1 and S phases, respectively. These results indicate that Dcw1p and Dfg5p are involved in bud formation through their involvement in biogenesis of the bud cell wall...

..In this review, we discuss a fundamental system that monitors glycoprotein folding in the ER and the unique roles of the sugar-recognizing ubiquitin ligase and peptide:N-glycanase (PNGase) in the cytosolic ERAD pathway...

Plant N-glycan processing enzymes employ different targeting mechanisms for their spatial arrangement along the secretory pathway

..Different plasmids are described as well as glycan analysis methods...

Cell type-dependent variations in the subcellular distribution of alpha-mannosidase I and II

A VelascoDivision of Cellular and Molecular Medicine and Center for Molecular Genetics, University of California, San Diego, La Jolla 92093 0651J Cell Biol 122:39-51. 1993

alpha-mannosidases I and II (Man I and II) are resident enzymes of the Golgi complex involved in oligosaccharide processing during N-linked glycoprotein biosynthesis that are widely considered to be markers of the cis- and medial-Golgi ..

..A model is proposed in which ERManI, by functioning as a downstream effector target of EDEM1, represents a checkpoint activation paradigm by which the mammalian UPR coordinates the boosting of ERAD...

..The amino acid sequence of this associated protein has no similarity to known plant alpha-L-fucosidases. These results show that EBM II is a novel alpha1,2-L-fucosidase and a protein complex containing endo-beta-mannosidase...

..The discovery of a similar signal in misfolded proteinase A supported the generality of the mechanism. These studies show that specific signals embedded in glycoproteins can direct their degradation if they fail to fold...

..M8A') by digestion with cytosolic alpha-mannosidase; series 2: oligosaccharides processed with Golgi alpha-mannosidases in addition to endoplasmic reticulum (ER) and cytosolic alpha-mannosidases; and series 3: glucosylated ..

..Although transfected NHK is primarily localized in the ER, some NHK also co-localizes with Golgi markers, suggesting that mannose trimming by Golgi alpha1,2-mannosidases can also contribute to NHK degradation.

Synthesis of beta-mannosides using the transglycosylation activity of endo-beta-mannosidase from Lilium longiflorum

..Thus, the lily endo-beta-mannosidase is useful for the enzymatic preparation of oligosaccharides containing the mannosyl beta 1,4-structure, chemical preparations of which have been frequently reported to be difficult...

A novel endo-beta-mannanase gene in tomato LeMAN5 is associated with anther and pollen development

..9b bearing an exocyclic ethylamine moiety proved to be a selective competitive inhibitor of alpha- and beta-mannosidases (K(i) = 6 nM) making it the most potent inhibitor of these glycosidases reported to date...

Molecular cloning and characterization of Arabidopsis thaliana Golgi alpha-mannosidase II, a key enzyme in the formation of complex N-glycans in plants

..A GFP fusion construct containing only the transmembrane domain was predominantly retained in the ER, a result that indicates the presence of a motif promoting ER export within the last 10 amino acids of the cytoplasmic tail of AtGMII...

Importance of carbohydrate positioning in the recognition of mutated CPY for ER-associated degradation

..For cases in which both lectins are involved, Cne1p and Htm1p play competing roles in targeting the substrate for degradation: loss of Cne1p accelerates degradation, whereas loss of Htm1p stabilizes the substrate...

Optimization of the production of thermostable endo-beta-1,4 mannanases from a newly isolated Aspergillus niger gr and Aspergillus flavus gr

..5 and 5.2 for A. sojae and P. pastoris, respectively. The enzyme from P. pastoris was more stable retaining most of the activity up to 50 degrees C, whereas the enzyme from A. sojae rapidly lost activity above 40 degrees C...

Comparison of kifunensine and 1-deoxymannojirimycin binding to class I and II alpha-mannosidases demonstrates different saccharide distortions in inverting and retaining catalytic mechanisms

b>Mannosidases are key enzymes in the eukaryotic N-glycosylation pathway. These enzymes fall into two broad classes (I and II) and are characteristically different in catalytic mechanism, sequence, and structure...

Endoplasmic reticulum-associated degradation of glycoproteins bearing Man5GlcNAc2 and Man9GlcNAc2 species in the MI8-5 CHO cell line

..N-glycan species, in particular Glc(1)Man(7)GlcNAc(2), were also found on the protein, indicating that several mannosidases might be implicated in the initial trimming of the oligomannoside...

N-glycan structure of a short-lived variant of ribophorin I expressed in the MadIA214 glycosylation-defective cell line reveals the role of a mannosidase that is not ER mannosidase I in the process of glycoprotein degradation

..In conclusion, P. pastoris is regarded as a suitable host strain for the production of blue mussel beta-mannanase. This is the first time a mollusc beta-mannanase has been characterized at the DNA level...

A highly thermostable endo-(1,4)-beta-mannanase from the marine bacterium Rhodothermus marinus

..The enzymes readily degrade the galactomannans from locust bean gum and ivory nut mannan but show no cross-specificity for xylan and carboxymethyl cellulose. There is no binding ability observed towards cellulose and mannan...

Morphological analysis of protein transport from the ER to Golgi membranes in digitonin-permeabilized cells: role of the P58 containing compartment

..Activity and mRNA levels appeared to be tightly co-ordinated. Tests of substrate specificity with the purified ManB enzyme showed that activity required a minimum of five mannose units to function efficiently...

Role of N-glycan-dependent quality control in the cell-surface expression of the AT1 receptor

..Together, localisation and association govern the assembly of complex glycans and thereby regulate interactions at the cell surface...

Overexpression of the Golgi-localized enzyme alpha-mannosidase IIx in Chinese hamster ovary cells results in the conversion of hexamannosyl-N-acetylchitobiose to tetramannosyl-N-acetylchitobiose in the N-glycan-processing pathway

..Furthermore, it provides a basis for understanding the human form of alpha-mannosidosis at the atomic level. The atomic coordinates and structure factors have been deposited in the Protein Data Bank (accession codes 1o7d and r1o7dsf)...

Matrix proteins can generate the higher order architecture of the Golgi apparatus

..The same compound inhibits recombinant human maltase glucoamylase, one of the key intestinal enzymes involved in the breakdown of glucose oligosaccharides in the small intestine, with a K(i) value of 21microM...

Steady-state localization of a medial-Golgi glycosyltransferase involves transit through the trans-Golgi network

Research Grants17

..role in vesicular transport of rhodopsin and other constituents of phototransduction, and (2) the family of mannosidases and their key roles in trimming carbohydrates in the ER and Golgi during rhodopsin biosynthesis...

..studies toward the chemical synthesis of various potential inhibitors of glycosidases, such as glucosidases and mannosidases, involved in the processing and biosynthesis of glycoprotein including gp120...

..of HIV gp145 to the endoplasmic reticulum using a KDEL tag which blocks exit into the Golgi and exposure to mannosidases. These high-mannose HIV Env molecules exhibited stronger reactivity with 2G12 than CHO-derived Env, suggesting ..